I have occational episodes of difficulty in breathing all sudden during night.After struggling for about half an hour, i gets the sleep. It is happening from last three to four years but only few times and every thing becomes all right by it self. I am a mouth breather since long. I have nasal allergy, but after coming to US it is no more and issue, but breathlessness hearts me many times and troubling my sleep. Is their some thing serious which could be related to my heart.